Paper felt



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Specification of Letters Patent.

Patented Aug, 2%

Renewed January $18, 1922.

@crlal lilo.

To aZZ whom it may concern Be it known that we, ALBERT L. Charts and Cameron BCLArr, both citizens of the United States, residing at Danvers, in the county of Essex and State of Massachusetts, have invented new and useful Improvements in Paper Felt, of which the following is a specification.

This invention has for its object to produce a sheet material suitable for the manufacture of wads for cartridges, and which may be manufactured by processes akin to those followed in making paper.

A gun wad shouldhave certain characteristics, i. it should be capable of a ten per cent reduction in thickness under a pressure of about ten pounds per sequare inch, and, on release of the pressure, it should return practically 98% to its original thickness, for reasons to which it is not necessary refer in detail Moreover, such wads should have. a smooth exterior surface and no internal holes or hollow spaces, should be capable of disintegration when the charge is exploded, and, while resilient, shouldnot be hard.

The present invention has, therefore, for its further objects to provide a sheet material having the optimum characteristics noted, and to manufacture the same from relatively inexpensive raw materials and by an inexpensive process.

The felt, which we shall describe, is formed of cellulose fiber, such as employed in making paper (e. g., mechanical or chemical wood pulp, or waste paper), wool combings or shearings or other 'wool waste, or cow hair. and long fiber cotton such as linters or cotton wast-e;

As an example of the procedure followed in producing the new product, we may instance the following Into a beating engine, we supply 500 parts wool (she'arings, combings or other waste wool or cow hair, or a mixture thereof); 550 parts sulphate pulp (sulphite pulp,

waste paper, or sulphate or sulphite screenings, if desired); 150 parts relatively long cotton fiber; and water in sufficient quan-' tity to enable the mass to circulate freely in the beater. This furnish is beaten long enough so that the components are thoroughly intermingled and the product is calpable of being formed into a web on the cy i der of a wet machine, so-called. The felt stock is now formed in convolutions on the forming cylinder of a wet machine, until a continuous sheet or cylinder of felt of the desired caliper is produced, whereupon the sheet is slit lingitudinally of the axis of the cylinder, and removed dried.

sheet of felt, made as herein described, is highly compressible resilient. it may be reduced in thickness 10% by the application of 10 pounds to the square inch, and, when released from pressure, its resiliency will cause it to assume 98.5% to 99% of its oi ginal thic mess or caliper. Moreover, it is smooth su ced, is free from holes or cavities, and is inexpensive to produce;

The wool or cow hair imparts to the sheet high degree of compressibility and resiliency, while the short fibers of the paper etc-cl; prevent the web from laminatiiig as it is formed into a sheet on the cylinder ine. With these two ingredients alone, -e proportions stated, the sheet would too tender and lack the necessary strength, but by the addition of the relatively long cotton fibers, the sheet is given the desirable matter, a furnish as herein described should not be beaten over four hours. We find it desirable to add about 5% of calcium hydroxide to the beater as this aids in re ducing the stock to a homogeneous mass. Moreover, in the cylinder machine the sheet undergoing formation should not be placed under high pressure between the end felt roll and the sheet forming roll, as such pressure makes the stock too hard. Baby or supplemental rollsshould be employed, to hold the blanket or felt against the sheet forming roll.

When gun wads are out from a sheet as herein described, they may be greatly compressed and reduced in thickness during the loading operation, without destroying their ability to expand to substantially their original thickness. They are sufliciently soft as to disintegrate when the charge of powder (or other explosive) is exploded, and thus prevent injury to the gun barrel.

What we claim is 1. A compressible resilient soft felt suit able for gun wads, capable of compression to about 90% of its bulk by a pressure of about 10 pounds to the square inch, and comprising wool or cowhair, paper stock, and cotton fibers in homogeneous admixture and felted relation.

2. A compressible resilient soft felt suitable for gun wads, comprising wool or cowhair, paper pulp and long cotton fiber in intimate admixture and felted relation, and

in the proportions of approximately 500 parts (by Weight) wool or cowhair, 550 parts paper pulp and 150 cotton fiber.

3. A process of making a compressible resilient felt suitable for gun wads, which comprises beating together with Water, wool or cowha-ir, paper-stock, and cotton fiber to form a homogeneous pulp, and forming the pulpy mass into a sheet of desired thickness.

In testimony whereof we have aflixed our signatures.

ALBERT L. CLAPP. CHESTER B. CLAPPn 

